The invention relates to a rail section in the form of a frog comprising two rail sections and guard rails held apart by liners, where at least the frog is passed through by a sleeve surrounding a connecting element such as a bolt.
Frogs are provided at points or crossovers by intersections of rail tracks. There are single, double and triple frogs, although the single frog is most frequently found in simple points.
In the frog, the guiding surfaces of the intersecting rail tracks are interrupted. The rail tracks continuing on from the tongues are angled in the vicinity of the frog and are called guard rails. The two tracks continuing from the ends of the points converge towards the frog tip. The tip can comprise either normal rails (rail frog), specially constructed rails that are then partially welded (partial block frog), or made in one piece (block frog). The latter are used only rarely by the German Railways (DB).
In the case of frogs made flora rails, these latter are frequently welded. This can however result in drawbacks when hard-to-weld materials are to be connected. A further drawback is that extraneous material is present in the abutting surface. Surface decarburizations are also a drawback. Furthermore, the risk of cracking increases.
If the rail parts are not welded to one another, they are held together by connecting elements such as bolts. The drawback here however is that a relative movement between the rail parts takes place.
Various designs of frogs are shown in DE 548 749, DE 23 18 419, DE 81 05 454 U1 or DD 60 326.